Sheathed valve



SHEATHED VALVE Filed Jan. 24, 1942 Patented July 16, 1946 SHEATHED VALVE Paul P. Johnson, Willoughby, Ohio, assgnor to yThompson Products Inc., a corporation of hio Application January 24, 1942, Serial No. 428,135

4 Claims. l This invention relates to headed articles such as poppet valves having a sheath amxed to the head for protecting the same against corrosion Y and heat. Y

v Specifically the invention relates to poppet valves having a thin sheet of corrosion and heatresistant metal covering the valve head and extending along the under side of the valve head to provide a valve seat together with a metal bond integrally aiiixing the sheath to the valve head and a puddled in bead of weld material sealing the bond metal.

According to this invention thev main valve body is made from metal such as steel which has desirable forging, machining and strength characteristics. Frequently, however, such steels will not-stand up in operation due to the hot corrosive atmosphere to which the valve heads are subjected. ForV example, exhaust valves in high speed, high compression engines operated with veryhigh octane gasoline are subjected to tremendous abuse since the hot corrosive gases must flow past the valve to the exhaust manifold. In order to protect the head area, of such valves, corrosion-resistant metals have been proposed but these metals are very expensive and frequently do not have the machinability and strength characteristics necessary for the valve body. VAccordingto this invention, therefore, the valve body itself is made of the usual machinable and workable metal'such as steel'and the valve head is covered with a sheath of corrosion and heatresistant metal such as a nickel-chromium alloy. The sheath is integrally aiiixed to the head area of the valve as by brazing andextends overthe peripheral edge of the valve head to underlap the valve head and define a valve head seat. 'I'he sheath can be made from forged or wrought metal and thus is more perfect than puddled-on metal which is prone to shrinks, blow holes and segregation.

The braze bond between the sheath and valve body improves heat now from the exposed surface of the operating valve thereby minimizing burning of the valve.

It is, then, an object of this invention to provide headed articles with sheaths for the heads thereof to protect the same against deterioration by surrounding atmospheres.

Another object of this invention is to provide a poppet valve with a protecting head sheath of corrosion-resistant metal.

A further object of the invention is to provide a poppet valve having a thin metal sheath covering the head thereof and brazed to the head.

A still further object of the invention is to seal a brazed bond between the head and sheath of a poppet valve.

Other and further objects of the invention will be apparent to those skilled in the art from the following detailed description of the annexed sheet of drawings which, by way of preferred examples, shows several embodiments of the invention. It will -be understood, however, that the invention is not limited to the illustrated embodiments.

On the drawing:

Figure 1 is a top plan view of a metal billet useful according to this invention to provide the body of a hollow valve.

Figure 2 is a side elevational View of the billet shown in Figure 1.

Figure 3 is a vertical cross-sectional view of a metal cap for the billet of Figures 1 and 2. A

Figure 3A is a transverse cross-sectional view of a brazing shim disk used to form the bond between the sheath and valve body and illustrating in dotted lines the manner in which the shim is cupped to cover all of the surfaces to be brazed together.

Figure 4 is a greatly enlarged fragmentary cross-sectional view of the cap and billet illustrating the mating surfaces thereof prepared for, a brazing operation.

Figure 5 is a vertical cross-sectional View of the billet of Figures 1 and 2 having the cap of Figure 3 brazed thereon and having a groove in the side wall thereof at the terminal end of the cap. e

Figure 6 is a fragmentary vertical cross-sectiona] view illustrating a step in the method of forging a poppet valve from the capped billet of Figure 5.

Figure 7 is a vertical cross-sectional view ofa hollow sheathed poppet valve body prepared from the blank of Figure 6 and having a welded bead seated in the groove of the blank to seal the brazed metal bond.

Figure 8 is a view similar to Figure 5 but illustrating the billet as being grooved prior to the brazing operation in accordance with a modied process according to this invention.

Figure 9 is a vertical cross-sectional view of the billet and cap shown in Figure 8 illustrating the same in brazed-together relation and also illustrating the welded-in bead sealing the brazed bond.

Figure l0 is a view similar to Figure 6 but illustrating the welded-in sealas being applied to the valve blank before it is completely formed into a valve in accordance with the modified process of this invention.

Figure 11 is a vertical cross-sectional view of a finished hollow poppet valve according to this invention made either from the process illustrated in Figures 1 to 'I or Figures 8 to 10.

Figure l2 is a fragmentary side elevational view, with parts broken away and shown in vertical cross section of a solid poppet valve having a cap with a depending rim flange disposed over the valve head.

Figure 13 is a fragmentary vertical cross-sectional view of a portion of the valve head shown in Figure 12 but illustrating the rim angefof the cap as being spun inwardly to underlap the valve head and also illustrating a welded-in bead protecting the bonding metal betweenV the cap,

and valve head.

Figure 14 is a view similar to Figure l2 but illustrating the nished sheathed valve head.

AAs shown on the drawing; Y

' In Figures 1,` 2 and 5 the referencenumeral I0 designates a solid cylindrical metal billet or slug having a reduced diameter head portion I-I at one endthereof. An annular shoulder I2 is thus provided at .the base of lthe vreduced portion II. The Ylength of thereduced portion Il isdeterminedby the type of valve vbeing made so that themetal v-in the reduced portion will form the valve head f Y The billet I is composed of metal such asian alloy steel which has desirable mechanical properties so that it can be machined, forged, and extruded to produce a hollow poppet valve body.

As best shown in Figure 3 a hollow circular cap .l

nickel and chromium.' Such an alloy is highly resistant te heat and corrosion.

The cap I3 has 'a cylindrical dependentrside wall I3a for snugly engaging the side wall of the reduced'portion*Ilv ofthe billet. The side wall I3al terminates ina rim edge ISb adapted to seat o'n'the shoulder- I2 of the billet.

As shown in Figure 3A, and in accordance with this invention, a` thin disk I4 of copper, silver or any suitable brazing metal or alloy is used to form the braze bond between the cap I 3 and billet portion Il.- The disk I4 is centeredover the billet portion II and the cap I3 is then pressed onto the billet thereby cupping the disk to the form shown in dotted lines. Alternately, of course, the cupcould-be preformed to fit on the billet and in the cap.

The cap I3A ts snugly on the billet Ill around theY head I I thereof so that the shim I4 is between all mating surfaces of thevcap and billet as shown in Figure 4. f

Any suitable bonding alloy 'having a melting pointat o-r below the forging temperaturesof the cap` and billet metals can be used. Alternately, the bonding metal could be electroplated in the cap I3 and on the billet portion II as an integral iilmfinsteadof as a separate shim.

The billet IU and cap I3 with the shim I4 therebetween is next heated in a'furnace preferably in a non-oxidizing atmosphere such as a hydrogen atmosphere to form a brazed bond I6 between all mating surfaces ofthe cap and billet as shown in Figure 5. The vcap is thus integrally brazed to the billet;

In accordance with one embodiment of this invention the billet with the cap brazed thereon next has a peripheral groove I'I cut therein at the exposed bond area between the cap and billet adjacent the rim edge I3b of the cap. As hereinafter explained this groove I'I is provided to form a pocket for a bead of welding metal having the same composition as either the cap or the billet to seal the brazed bond.

The billet III with the cap I3 brazed thereon is next die pressed and extruded around a stake to provide a hollow valve blank I8 as shown in Figure 6. The valve blank I8 has an outwardly aring neck portion I9 containing the groove II and a head portion' 20 covered with the cap I3. The die pressing operation deforme the billet metal to provide the head 20 and also deforrns the cap metal so that the ange I3a thereof will underlap the head and partially cover the neck portion I9 as at 2|. This underlapping portion 2| is adapted to provide a seat for the head of the nished' valve. The die pressing or forging is preferably carried out at eleva-ted temperatures close to the brazing temperature and improves the braze bond IS. Thus any flaws in the bond are corrected.

' As shown in Figure '7 the blank I8 of Figure 6 is further forged and'coined to provide a valve body 22 having a hollow head portion and hollow stem portion with an enlarged nubbin end 22a. The groove I'I in the neck portion I9 of the valve body is next filled with welding material 23 of the same or similar composition as either the billet metal IB or the cap metal I3. The weld metal 2S can be puddled into the groove Il and will completely seal all exposed bonding metal between the cap and valve body. The bonding metal is less corrosion resistant than the sheath metal or valve body metal `and it is thus highly desirable to seal the bond against exposure to corroding atmospheres. A bead of thewelding metal will project as a rim around the neck I9 and this bead can be ground off ush with the cap and neck as shown in Figure 11 to provide the finished valve head.

`As shown in Figure 11, the finished valve 24 has a hollow stem 25, a hollow head 25 covered by a sheath 2 of the cap metal, and an outwardly flaring neck 28 between the stem and head partially covered by the underlapped portion of the sheath to provide the valve head seat 29. This valve head seat terminates at the weld area 30. All brazing material between the sheath and valve head is completely sealed by the weld area 3U.

The hollow valve 24 has a coolant C such as metallic sodium therein. The nubbin 22a of the valve body 22 is swaged or extruded to form a closed end 25a on the stem 25 thus sealing the coolant C in the valve.

The hollow valve of Figure 11 can also be made by the process illustrated in Figures 8 to 10, wherein the cap I3 is mounted on the reduced head II of the billet I0 as shown in Figure 8 but the billet already has the groove I'I therein.

The cap is then brazed to the grooved billet as shown in Figure 11 and the groove I'I is iilled with the bead of welding material 23 as described in connection with Figure 7. `The capped billet, vafter the brazing and welding operations, is next die pressed and yextruded to provide the blank I8a of Figure 10. The blank Illa differs from'the blank I8 in that the weld metal 23 is already in position. The valve body 22fof Figure 7 and the finished valve 25 of Figure 11 are then metal.

ductivity away from the exposed valve head sur- 65 successively made from the blank |8a as described above.

Thus, according to the alternative processes dened above, the weld metal seal for the brazing material can be made either before or after the forging operation for producing a valve bodir from the solid metal billet.

In the embodiment shown in Figures 12 to 14 a solid poppet valve 40 is made in accordance with known forging processes to provide a Valve stem 4I with an outwardly Haring end portion 42 providing a valve neck and a valve head 43. In accordance With this invention the valve head 43 is machined to provide an angular shoulder 44 around the under side thereof inwardly from the periphery of the head.

The machined valve head is then electroplated to deposit a lm of brazing metal thereon. A cap 45 similar to the cap I3 described above is provided with a depending rim ange 45a terminating in a rim edge 45h. The cap 45 has the interior surfaces thereof covered with a film of electrodeposited brazing material of the same composition as the electrodeposited material on the head 43 of the valve. over the head 43 of the valve with the rim 45a depending below the side of the valve head as shown in Figure 12.

If desired as explained above the brazing shim 5 sheath metal is selected for its heat and corro` face thereby minimizing burning of the valve in operation. The sheath metal extends over the peripheral edge of the head and underlaps the head to provide a seating surface therefor. The

15 otherwise than necessitated by the scope of the appended claims.

I claim as my invention:

l. A poppet valve comprising a metal valve body dening a valve stern with an outwardly flaring neck portion terminating in a valve head The cap45 snugly iits 25 I4 can be used in place of the electroplated films. 30

The depending flange 45a of the cap is next spun into abutting engagement with the under side of the valve head as best shown in FigureV 13 and the cap and head are heated in a nonoxidizing atmosphere as described above to melt the electrodeposited brazing lms or the shim to effect a brazed bond 46 between the cap and head. The spun in portion 45a of the cap terminates in spaced relation from the shoulder 44 of the valve head and thereby defines, with the shoulder, a groove for receiving the puddled-in weld material 41.

The projecting portion of the weld material 41 is next ground ush with the valve neck portion 42 as shown in Figure 14 to provide the finished valve. This valve has the head 43 thereof sheathed with the cap 45 and has a seat 43 defined by the cap metal. The exposed ground off weld metal provides a seal 49 for the brazing material, and extends around the neck portion 42 of the valve adjacent the valve seat 48.

The process of Figures 12 to 14 can also be used to make hollow valves and could be effected with the valve body 22.

Likewise solid sheathed valves could be made from capped billets as described in connection with Figures 1 to 11.

From the above descriptions it will be understood that this invention now provides headed articles with integral thin metal sheaths covering the heads thereof and aiixed to the head by means of bonding metal which is sealed between the head and sheath with a puddled-n weld The bonding metal increases heat conof larger diameter than the stem, a thin metal sheath completely covering said head and extending over the peripheral edge of the head, said sheath having an inturned portion underlapping the head to define a valve seat, a metal bond including metal different than the body and sheath metals integrally joining the sheath and body, and a metal bead weld in said neck portion of the body adjacent the head underlapping portion of the sheath sealing the bond metal said metal bead weld being composed of a metal selected from the group consisting of metal forming the valve body and metal forming the sheath.

2. A poppet valve having a heat and corrosionresistant thin metal sheath completely covering the head, said sheath having a dependent rim flange underlapping the head to dene a. seat for the head, a brazing metal bond integrally uniting the sheath and valve head, and a seal 40 of weld metal diierent than the brazing metal and selected from the group consisting of metals having substantially the same composition as the valve head and metals having substantially the same composition as the sheath metal around the terminal edge of the cap sealing the bond.

3. A composite hollow poppet valve comprising a body member having a hollow stem portion and a hollow domed head portion composed of machinable stress-resisting steel, a corrosion and 50 heat-resistant metal cover on the dome of said 00 sheath covering the head of said body, a rst metal bond integrally uniting the sheath and body, and a second metal bond connecting the periphery of said sheath with said body and sealying the first bond.

PAUL P. JOHNSON. 

